In performing X-ray imaging angiography of the lower limbs of a patient, imaging usually starts at the pelvis and ends at the foot. The size of an imaging system X-ray radiation detector dictates image size. Thus, several images are acquired in a sequence of steps in order to cover an entire limb. The acquired images are joined (e.g., sewn) together and the entire limb image is created if so desired. Since each image is of a different part of the body, X-ray absorption differs in each X-ray imaging step. The X-ray radiation needs to be regulated and optimized for optimum image quality for individual steps.
In known systems, Peripheral Angiography workflow involves many user interactions. A user first performs X-ray imaging in individual steps (e.g., from the pelvis to the foot) on the patient lower limbs for configuration and to manually adjust a collimator, semi-transparent filters and finger filters for each step. A collimator narrows an X-Ray beam to cause the spatial cross section of the beam to become smaller and comprises individual plates or a diaphragm or system of diaphragms made of an absorbent material and arranged to determine the dimensions and direction of an X-ray beam of radiation. Semi-transparent filters attenuate particular (or all) wavelengths of X-ray radiation provided from a radiation source collimator to a portion of a patient and a finger filter attenuates substantially all X-ray radiation provided from a radiation source collimator to a portion of a patient.
A user further performs X-ray imaging in individual steps on the patient lower limbs (from foot to pelvis) to determine a mask for subtraction of background detail. A third X-ray imaging pass is performed in individual steps on the patient lower limbs (from foot to pelvis), following injection of an X-ray contrast agent into the patient, to obtain desired X-ray images. In moving through the sequence of steps, the forward speed of movement of an X-ray source and detector combination relative to a patient table, is controlled by a user via a switch, for example. Known X-ray imaging of the limbs is cumbersome, involving multiple imaging passes and multiple steps as well as manual adjustment of a collimator, semi-transparent filters and finger filters for each individual step. A system according to invention principles automates a substantial portion of the process and addresses associated problems.